1. Field of the Invention
The present invention relates to a displaced position detecting device for converting a mechanical displacement into an electric signal. More particularly, this invention relates to an improved device capable of detecting a mechanical displaced position by utilizing the propagation time of a signal advancing in a magnetostrictive wire.
Devices according to the present invention are effective in application to positional feedback means in an automatic balance instrument, a level meter, a differential pressure transmitter and so forth.
2. Description of the Prior Art
The conventional displaced position detecting devices available heretofore for a position feedback means in an automatic balance instrument include a potentiometer, an induction potentiometer capable of converting into an electric signal a magnetic imbalance based on an angle of rotation, a flux bridge, a magnetic displacement modulator and so forth. Of these devices, the one employing a wire-wound potentiometer has disadvantages that the resolution is limited by the number of turns of the coil and also that a thermo-electromotive force is generated due to frictional heat between a slide brush and a wire resistor to cause harmful influence in the form of noise. Moreover, the service life is affected by friction. In the induction potentiometer, flux bridge and magnetic displacement modulator, there exist disadvantages of high cost and complicated structure although an advantage is found in the point that no mechanical contact component is employed.